Fluid Dynamics

If wind blows at 25m/s over your house, what is the net force on the roof if its area is 240m² and is flat?

Fluid Dynamics

During each heartbeat, approximately 70cm³ is pushed from the heart at an average pressure of 105mm-Hg. Calculate the power output of the heart, in watts, assuming 70 beats per minute. *please explain this as simply as possible- thanks so much :)

Torque, center of mass

The masses of the Earth and Moon are 5.98 x 10^24kg and 7.35 x 10²²kg, respectively, and their centers are separated by 3.84 x 10^8 m. (a) where is the CM of this system located? (b) what can you say about the motion of the Earth-Moon system around the sun, and of the Earth and Moon separately around the Sun? *note- ple ...continues

Torque, center of mass

A person exerts a force of 38N on the end of a door 96cm wide. What is the magnitude of the torque if the force is exerted (a)perpendicular to the door and (b)at a 60.0° angle to the face of the door? *note- please explain this in the simplest terms possible for me- thank you so much :)

Equilibrium

A 67.0kg adult sits at one end of a 10.0m board, on the other end of which sits his 23.0kg child. Where should the pivot be placed so the board (ignore its mass) is balanced?

Equilibrium

A 170cm tall person lies on a light (massless) board which is supported by two scales, one under the feet and one beneath the top of the head. The two scales read, respectively, 31.6kg and 35.1 kg. Where is the center of gravity of this person?

Hydrogen and Oxygen molecules

Hydrogen and Oxygen molecules in a gas sample have the same temperature. This means the hydrogen molecules, on the average have the same? i'm looking for the type of effect concerning kinetic energy and speed.

Volume

a block of wood half as dense as water floats with half its volume above water. A piece of iron is then tied on top so the wood floats with only 1/4 its volume above surface. If the wood and iron are turned over so that the iron is submerged beneath the wood, then the volume of wood above the water surface will be? Why?

Elements

If a pair of helium nuclei are fused together, the result is, and why?

mass/buoyancy

Taking buoyancy of air into account, which has the greater mass? A large block of wood or a smaller block of iron on weighing scales and both having the same weight- 1 ton.